Functional connectivity networks are disrupted in left temporal lobe epilepsy

Waites, Anthony B.; Briellmann, Regula S.; Saling, Michael M.; Abbott, David F.; Jackson, Graeme D.

doi:10.1002/ana.20733

Cited by 289 publications

(234 citation statements)

References 54 publications

Supporting

Mentioning

212

Contrasting

Unclassified

Order By: Relevance

“…Differences on connectivity alterations between left and right MTLE have been previously described in the literature [Haneef et al, 2015; Pereira et al, 2010; Waites et al, 2006]. Through diversified methodologies, these studies explored distinct aspects of brain functional connectivity using anatomical or functional relevant ROIs, independent component analysis and graph theoretical information.…”

Section: Discussionmentioning

confidence: 97%

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Campos

Coan

Yasuda

et al. 2016

Human Brain Mapping

108

102

View full text Add to dashboard Cite

Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large‐scale RSNs is differently affected in patients with right‐ and left‐MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled in 70 regions of interest (ROIs), from resting‐state functional‐MRIs of 99 subjects (52 controls, 26 right‐ and 21 left‐MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF2C‐toolbox, which provided ROI‐wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right‐MTLE. Both groups showed abnormal correlation between the dorsal‐DMN and the posterior salience, as well as between the dorsal‐DMN and the executive‐control network. Patients with left‐MTLE also showed reduced correlation between the dorsal‐DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left‐MTLE expressed a low cluster coefficient, whereas the altered connections on right‐MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right‐ and left‐MTLE patients with HS have widespread abnormal interactions of large‐scale brain networks; however, all parameters evaluated indicate that left‐MTLE has a more intricate bihemispheric dysfunction compared to right‐MTLE. Hum Brain Mapp 37:3137–3152, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

show abstract

Section: Discussionmentioning

confidence: 97%

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Campos

Coan

Yasuda

et al. 2016

Human Brain Mapping

108

102

View full text Add to dashboard Cite

show abstract

“…It has been suggested that changes in functional connectivity can be used as an early marker of some diseases. Decreased correlations have been reported involving the hippocampus of patients with Alzheimer's disease [82;83], the motor cortices and frontal regions of multiple sclerosis patients [84;85], and the left hemisphere language network of left temporal lobe epilepsy patients [86]. Changes in functional connectivity have been detected in patients with schizophrenia [87;88] and attention deficit hyperactivity disorder [89].…”

Section: Intrinsic Variancementioning

confidence: 99%

Assessing functional connectivity in the human brain by fMRI

Rogers

Morgan

Newton

et al. 2007

Magnetic Resonance Imaging

394

279

View full text Add to dashboard Cite

Functional magnetic resonance imaging is widely used to detect and delineate regions of the brain that change their level of activation in response to specific stimuli and tasks. Simple activation maps depict only the average level of engagement of different regions within distributed systems. FMRI potentially can reveal additional information about the degree by which components of large-scale neural systems are functionally coupled together to achieve specific tasks. In order to better understand how brain regions contribute to functionally connected circuits, it is necessary to record activation maps either as a function of different conditions, at different times or in different subjects. Data obtained under different conditions may then be analyzed by a variety of techniques to infer correlations and couplings between nodes in networks. Several different multivariate statistical methods have been adapted and applied to analyze the variations within such data. An approach of particular interest that is suited to studies of connectivity within single subjects makes use of acquisitions of runs of MRI images obtained while the brain is in a so-called steady state, either at rest (i.e. without any specific stimulus or task) or in a condition of continuous activation. The interregional correlations between fluctuations of MRI signal potentially reveal functional connectivity. Recent studies have established that interregional correlations between different components of circuits in each of the visual, language, motor and working memory systems can be detected in the resting state. The correlations at baseline are changed during the performance of a continuous task. In this review the various methods available for assessing connectivity are described and evaluated.

show abstract

“…While structural “network disease” is unlikely to explain cognitive impairment in all cases,9 the underlying concept can be expanded to incorporate functional network disease as well. From this perspective some of the cognitive deficits in TLE, and indeed in epilepsy more generally, represent alterations in functional networks 9, 10, 11…”

Section: Introductionmentioning

confidence: 99%

Cognitive impairment in epilepsy: the role of reduced network flexibility

Tailby

Kowalczyk

Jackson

2017

Ann Clin Transl Neurol

Self Cite

View full text Add to dashboard Cite

ObjectiveThe dominant model of cognitive impairment in focal epilepsy has emphasised structural bases for cognitive deficits. Current theories of cognition in the healthy brain emphasise the importance of the reweighting of brain network interactions in support of task performance. Here, we explore the hypothesis that cognitive deficits in epilepsy arise through abnormalities of dynamic functional network interactions.MethodWe studied 19 healthy controls and 37 temporal lobe epilepsy (TLE) patients, using a behavioural measure of verbal fluency (the Controlled Oral Word Association Test) and an fMRI verbal fluency paradigm (Orthographic Lexical Retrieval).ResultsBehaviourally, verbal fluency was significantly impaired in TLE. Psychophysiological interaction analyses of the fMRI data, which capture state‐dependent changes in network connectivity, revealed reduced task‐dependent modulations of connectivity from left superior medial frontal cortex to left middle frontal gyrus in TLE patients. Individual differences in verbal fluency among TLE cases was correlated with task‐dependent changes in connectivity from left posterior cingulate to left superior medial frontal cortex, and from left superior medial frontal cortex to a range of right predominant brain areas.InterpretationThese data reveal that the typical pattern of task‐driven shifts in network connectivity is not observed in TLE. Our observations go beyond simple structure‐function associations and suggest that failure of network flexibility can be an important contributor to cognitive impairment in epilepsy.

show abstract

Functional connectivity networks are disrupted in left temporal lobe epilepsy

Abstract: We suggest that this reduced connectivity in left temporal lobe epilepsy may reflect a disturbance of the language network during resting state in patients and may be related to subtle language difficulties in this patient population.

Cited by 289 publications

References 54 publications

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Assessing functional connectivity in the human brain by fMRI

Cognitive impairment in epilepsy: the role of reduced network flexibility

Contact Info

Product

Resources

About